1. EQ1: How do we inherit traits from our parents? EQ2: Is inheritance predictable?

2. What is Genetics? Genetics is the scientific study of heredity

3. What are Genes? Genes are the sequence of DNA (A, T, C, G) that codes for a protein and thus determines a trait. Ex. Hair color

4. What is a Trait? A trait is a specific characteristic that varies from one individual to another, one of several options for a gene. Examples: Brown hair Tongue rolling Free earlobes

5. What is an Allele? Alleles are the different possibilities for a given trait. Scientists give them a letter to represent the possibilities (1 letter represents 1 whole gene- a loooong piece of DNA ex. Your eye color). The letter chosen doesn’t matter Capital or lowercase DOES matter [make sure they look different!] Every trait has two alleles (one from the mother and one from the father) Example: Can roll tongue = Rr Mom’s egg gave you a R allele (Can roll) and Dad’s sperm gave you a r allele (Can’t roll) so you probably have “Rr” (Can roll- R wins over r) Examples of Alleles: B = Brown Hair b = Blonde Hair

6. If my dad has brown eyes, why do I have blue eyes?

7. Practice: Gene, Trait or Allele? r = can’t roll tongue Allele!

8. Practice: Gene, Trait or Allele? Eye color Gene!

9. Practice: Gene, Trait or Allele? F = free earlobes Allele!

10. Practice: Gene, Trait or Allele? Blue eyes Trait!

11. Practice: Gene, Trait or Allele? B = Brown eyes Allele!

12. Gregor Mendel Father of Genetics 1 st important studies of heredity Identified specific traits in the garden pea and studied them from one generation to another

13. Mendel’s Conclusions 1. Law of Segregation – Two alleles for each trait separate when gametes form; Parents pass only one allele for each trait to each offspring 2. Law of Independent Assortment – Genes for different traits are inherited independently of each other Just because you got your mom’s hair doesn’t mean you have to get all the traits of mother

14. Dominant vs. Recessive Dominant – Masks (covers) the other trait; the trait that shows if present. Usually more common Represented by a capital letter Recessive – Less common. An organism with a recessive allele for a particular trait will only exhibit that trait when the dominant allele is not present; Will only show if both recessive alleles are inherited Represented by a lower case letter R r

15. Dominant & Recessive Example TT - Represent offspring with straight hair Tt - Represent offspring with straight hair *T still wins, but your children could get curly hair! tt - Represents offspring with curly hair T – straight hair t - curly hair

16. Genotype vs. Phenotype Genotype – The genetic makeup of an organism; The gene (or allele) combination an organism has. Example: Tt, ss, GG, Ww Phenotype – The physical characteristics of an organism; The way an organism looks Example: Curly hair, straight hair, blue eyes, tall, green peas

17. Genotype vs. Phenotype Genotype: The allele combination inherited from the parents. Ex: Genotype (Genetics say) = Bb Phenotype: The observable characteristics of the genotype inherited. The organism’s appearance or trait expressed. Ex: Phenotype (PHysical appearance for Bb)= Brown hair

18. Practice: Genotype or Phenotype? Brown hair Phenotype!

19. Practice: Genotype or Phenotype? Rr Genotype!

20. Practice: Genotype or Phenotype? bb Genotype!

21. Practice: Genotype or Phenotype? Hitchhiker’s thumb Phenotype!

22. Practice: Genotype or Phenotype? Straight hair Phenotype!

23. Practice: Genotype or Phenotype? Tt Genotype!

24. Homozygous vs. Heterozygous Homozygous (purebred) – Term used to refer to an organism that has two identical alleles for a particular trait (TT or tt) Heterozygous (hybrid) - Term used to refer to an organism that has two different alleles for the same trait (Tt) RR RrRr rr

25. Homozygous vs. Heterozygous Homozygous Dominant: Homozygous Recessive: Heterozygous: RR RrRr rr

26. Practice: Homozygous dominant, homozygous recessive, or Heterozygous? HH Homozygous dominant!

27. Practice: Homozygous dominant, homozygous recessive, or Heterozygous? Ee Heterozygous (one dominant & one recessive allele)!

28. Practice: Homozygous dominant, homozygous recessive, or Heterozygous? bb Homozygous recessive!

29. Practice: Homozygous dominant, homozygous recessive, or Heterozygous? Uu Heterozygous (one dominant & one recessive)!

30. Allele Practice WS pg. 12 Let’s make sure you get how the genetic code works before we get into using the code!